Changes in 20201214091023

Built from de82276dbe0fc291c5d9526a7dbc1b736010873a

..index..
Bug 1681671 R[Core:Graphics: WebRender]Crash in [@ __memcpy_avx_unaligned | webrender::renderer::Renderer::draw_frame]
Bug 1681921 R[Core:Graphics: WebRender]Ship WebRender Software to Windows nightly users with small screens
Bug 1682146 R[Core:Graphics: WebRender]ClearCache bitflags are all identical
Bug 1675073 R[Core:ImageLib]Intermittent gtest timeout during ImageDecoders.AVIFStackCheck
Bug 1662816 R[Core:Layout]Intermittent /intersection-observer/timestamp.html | Generate notifications. - assert_between_inclusive: Notification to top window observer is within the expected range. expected a number greater than or equal to 630.22 and less than or equal to 673.18 b
Bug 1671764 R[Core:Spelling checker]Don't select random en-* dictionary when lang attribute is en, not en-US
Bug 1487181 R[Core:Web Painting]Elements with perspective and overflow: scroll set do not properly clip children with active layers
Bug 1679058 R[Firefox Build System:Lint and Formatting]Print Version of Codespell in logs
Bug 1679758 A[Firefox Build System:Lint and Formatting]Remove empty lines at the end of files
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Changes to 9 bugs - 8 fixed.
1 bugs are not included due to being restricted